Telegraph system



J. H. BELL.

TELEGRAPH SYSTEM.

APPLICATION FILED NOV. 22, 1917.

Patented July 22, lJlJ.

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TELEGRAPH SYSTEM.

APPLICATION FILED NOV- 22,1917. 7 1,3 10,595, Patented J 1113*22, 1919.

2 SHEETS-SHEET Z.

Mve 17702 (fa/m #560.

UNITED STATES PATENT new JOHN H. BELL; OF SOUTH ORANGE, NEW JERSEY, ASSIGNOR T WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK N. Y., A CORPORATION OF NEW YORK.

TELEGRAPH SYSTEM.

Specification of Letters Patent.

Patented July 22, 19219.

To all whom it may conccrn.

relay.

Be it known that I, Jonx II. Bonn, acitizen of the I nited States. residing at South Orange, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Telegraph Systems, of which the following is a full, clear, concise. and exact description.

This invention relates to telegraph systems. and more particularl to telegraph'repcating systems.

The principal object of this invention is to provide an improved system for handling so-callcd halt-duplex telegraph service.

In accordance with this invention. messages may be repeated from a duplexed main line to a plain or non-duplexed extension line by means of a line relay and a control In turn. a so-callcd self-aiding relay is employed for repeating telegraphic signals from the extension line to the duplexed line.

This invention is illustrated diagrammatically in the :u-com1mn 'ing drawing. in which only so much of a telegraph equipment has been shown as will be necessary to a clear mulerstanding of the system.

I11 the drawing. I igure'l is shown a telegraphic equipment suitable for halt-duplex working between two remote substations: in Figs. :2 and 3. respectively. are shown alternate arrangements of the equilnncnt shown in Fig. 1.

Referring to the drawings, a main line indicated by the reference character Lextcnds between two central stations. A and It. from which extension line's 4 connect to branch or substations and Il), respectively. Since a clear umlerstanding:of the system may he had by tracing the. operations which take place in the transmission of a message, say from the station to the station D. let. it now be assumed that a key switch 2 at the station C is moved to its open position. This operation disconnect-stile corresponding extension line circuit, which inay be traced through a line relay 3. the local contacts of which have. not, however. been shown, a, line conductor 4. the. contacts 11 ot a polarized control relay sounder 10, a conductor H, a winding 21 of a. self-aiding mlarizedpole-changer relay" 20, to a grounded current source 9. (essal ion of current through the winding 21 of the relay 20 results in the armature of this relaybein'g b5 moved to disconnect a battery 5 from, and to circuit bein interrupted as described, the

weaker current in the coil 22 being unopposed is sutlicicnt to more the armature of this relay to its left-hand position. This operation establishes a circuit which may be traced from the battery (3, over the armature ot' the relay :20 to the apex or neutral connective point on the polar duplex equipment of the hue L. which is intermediate the coils of a polarized line relay 30. From this point current from the battery (3 divides between the left-hand winding of this relay and an artificial line AL toearth, and the righthand windings of this relay'by way of the main line I, and the windings of a polar relay 230 and an artificial line AL to earth at the distant central station I). Since the equipments at the points A and f are respectively typical of the equipments at the points B and 1). similar reference characters have been employed in designating like parts in all of the. equipments. At the station A a portion of the outgoing current from relay 21) may also'be traced through a branch or leak circuit formed by a resistance unit 28. a winding 1240f the relay 2 and a resistance unit 21 to earth. 1 t the station B the current as traced through the relay 30 moves the armature thereof to disconnect a battery 7, and to connect a battery 8. through the winding ot a polarized relay 10 to earth. The latter relay is" thereby moved to separate its contacts 11 and to close its contacts 12. The contacts ll dis connect. the line circuit 4 which extends through a line relay 3 and key switch to earth at. the substation D. At this moment,

a circuit may also hetraced from the battery 9 and the winding 21 of the polarized relay 20, the contacts 12 of the relay l0, andto the station I), the relay 10 also substitutes the resistance 13 for the circuit to that station, in order that the circuit will not be interrupted through the winding 21 of the relay 20, whereby the armature of the latter relay will be retained in circuit with the battery 5. On the sending key 1 at the station G being closed, current through the wind ing 21 of the relay 20 atA overpowgrs the effect of current throughthe windin" 22 of this relay, whereupon its armature willfoe moved to engage the battery 5 and current therefrom will transverse the circuits already traced, to oppositely bias the relay 30 at B,

which accordingly connects the source of current 7 through the relay 10. This current being of opposite polarity to the current traced from the battery 8, it will oppositely bias the relay 10, which thereupon establishes its contacts 11 and separates its contacts 12, thereby disconnectin the resist ance unit 13 and substituting t erefor the extension line 4 of the substation D, in a manner similar to that already described. In moving to its opposite position, the armature of the relay 10 closes its contacts 11 before its contacts 12 are separated; therefore.

no interruption of current through the winding 21 of the relay 20 at B takes place and the armature of this relay is accordingly held on its normal bias to engage the source of current 5.

From the foregoing description, it will be clear that in response to the key 1 at the substation C, the relay 20 at A will establish changes of current polarity over the line L to correspondingly operate the line relay 30 and in turn the local control relay 10 at the station E, and that such operation of the relay l0 establishes opening and closing of the extension line 4, whereby the line relay 3 and local sounder equipment controlled thereby (not shown) at the substation D, will respond in translating a message.

Directing attention to the vibrating or self-aiding feature employed with the pole Gil the latter windings with respect to the wind- V nns 21 and 322, is such that discharges from changer relays 20, a circuit may be traced from a grounded condenser 27 through windings 23 and 24 of this relay, and a resistance unit 26, to earth. This condenser will be charged by either the battery 5 or the battery 6, depending upon the position of the relay armature; and. it will furthermore-be obvious that on the instant the armature of the relay 2O separates from either one cl its contact stops and before arriving at the opposite contact stop, the condenser 27 will discharge over the series circuit already traced through th windings 25 and 24: of this relay. he relation of this current action through the condenser 27 will be in phase with the respective action of current through the winding 21 or 22, and reby serve to aid respectively the latter windings in moving the armature of this relay. The proportions of the winding 24 and the resistance 26 are such that the direct current present at any moment therethrough, will be in a direction to relieve the polarizing or biasing effect on the relay armature. It may be pointed out, however, that on the instant the arumture establishes either one or the other of its circuits, the condenser 2'2 will receive a charge thrbugh the winding 23 which will set up action differential to or neutralizing with respect to the direct current through the winding 24:, thereb permitting the armature to establish a su 'ciently long interval of contact in responding to current through either the winding 21 or 22 in the relations already described.

In telegraph workin essary to efi'ect a -03% a receiving operator may interrupt the sending operator in order to transmit in the oposite direction. In describingbreak service, as carried out by the present system, let it now be assumed that while a message is under transmission from the substation C, that an operator at the substation l) may have occasion to interrupt the message. The key switch 2 at'D is accordingly moved to its open position, thereby disconnecting a circuit which extends from the battery 9 at B through the winding 21 of the relay 20, whereupon current through the'winding 22 causes the armature of this relay to establish the battery 6 with the outgoing connective point on the duplexed equipment of the main it is frequently nocled break, whereby i line L. At the station A, the line relay 30 responds to this current and connects the battery 8 vhrough the winding of the polarized cbntrol relay 10, to earth; Contacts 11 ads opened while the contacts 12 are Cessation of operation of the line relay 3 and its local sounder (not shown) at G, indicates a break signal to the operator at that point; the key switch 2" will therefore be moved to its closed position, thereby permitting the operator at D to transmit to the station Gin a manner similar to that already described in connection with transmission from the station C to the station D.

Since the equipment at the two ends of the main line L is identical, as already mentioned, it will be clear that message signals and break signals may be effected from one end of the line in a manner identical with the operations for the same service in tht l posits direction. j i

Referring to Fig. 2 of the drawing, while this alternate arrangement provides that service results, similar to those already described in connection with Fig. 1, may be attained, the operations are carried out in a slightly different manner. For convenience of description, however, characters of reference similar to those employed in the arrangement already described have been used in designating like or correspondingly operating parts in the alternate arrangement.

10 Although only a repeater equipment is shown at A and a substation equipment is shown at C,it will be understood that a main line L extends to a distant repeater station at which an equipment similar to that shown at A is employed in connection with equipment at a second substation typical of the substation C; For purpose of description, let it be assumedthat a message is under transmission from the substation C by way of the main line L to thevdistant' substation. In response to operation of the transmitting key 1, interruptions will be effected in a circuit which may be traced through the line relay 3, line conductor 4, the contacts 11 of the relay 10, the conductor 14, the windings 21 of the relay 20, to the battery 9. The

relation of the windings 21 and 22 of this relay are the same as the relation of the same windings in the corresponding pole changer relays already described, in connection with Fig. 1. Therefore, in response to opening and closing of the line 4, the armature of the relay 20 will be rocked to alternately connect the sources of current of 5 and 6 with the line, L, thereby setting up operations at the distant repeater stations which are translated into the extension line of the distant substation. In order to accelerate the operation of the pole changer relay 20,

its windings 23 and 24:; are connected and operate in a manner similar to the corresponding windings on the self-aiding pole changer relays already described in connection with Fi 1 In describlng'jthe operations whereby an incoming message, may be received at the substation C, changes of current polarity established in the line L by adistant transmitter in a manner similar to the polarity changesalready described, as set up in transmitting from a substation C, will cause the armature of the polar relay 30 to be moved to alternately connect the sources of current 7 and 8 through the winding of the control relay 10. At the instant the armature of the relay 30 is connected with the battery 8, the

' armature of, the polar relay 10 will be biased to its opposite or negative position, thereby separatlng its contacts 11 and 12, and closing its contacts 15. The time relation of the contacts 11 and 15 are such that the latter contacts will be closed in advance of the separation of the contacts 11 and vice versa. Disconnection of the contacts 11 opens the circuit of the line circuit 4 to the substation C, while separation of the contacts 12 disconnects winding 22 of relay 20. A circuit may also be traced from the battery 5, and armature of the relay 20, through the resistance unit 28, winding 23 of thisrelay, "0 contacts'15 of the relay 10, and a resistance unit 13, to earth. It will be clear that the described operation of the relay 10 substitutes current through the winding 23 and the resistance unit 13 for current normally 5 established through the winding 21 of this relay and the substation line 4. The connective relation between the coils 21 and 23 is such that the circuit changes at the relay 10 do not permit the relay 20 to operate, the 8 current through the winding 23,. acting in the'same direction on the armature as the current previously flowing through its winding 21. On responding to a correspondingly poled impulse of current from the line L, 8 the arn'iature of the relay 30 connects with the battery 7, whereupon the relay 1O will be oppositely biased to close its contacts 11 and 12 and to separate its contacts 15, there by completing a circuit from the battery 9 0 through the winding 21 of the relay 20 to the substation line 4, and also to restore the normal connection through the winding 22 in substitution of the onnection through the winding 23 of the relay 20. In this manner, incoming impulses from the line L are repeated into the substation line 4.

In order to initiate a break signal from the station C to interrupt an incoming message, a key switch (not shown),similar to the 1 switch 2 shown in Fig. 1, will be moved to its open position, thereby opening the line 4 and causing cessation of current through the winding 21 of the relay 20, Current present through the winding 22, which may 05 be traced from the source 9, contacts 12 of the relay 1,0, and the resistance unit 13, to earth, thereupon moves the armature of the relay 20 into engagement with the battery 6. thereby establishing an outgoino impulse of negative current with the (hip exed line L, which on arrivin at the distant station, opcrates a polar re ay corresponding with the line relay 30, and in turn a control relay, as the relay 10 to intcrrupt the line to the as sociated substation. These operations take place in a manner similar to the operations. already described in connection with the receipt of a message at the station C.

In describingthe alternate arrangement shown in Fig. 3 of the drawing, it will be understood that equipment typical of that shown at A and C may be present at a corresponding distant central and substation on the line L. Therefore, in tracing outgoving message signals from the substation C,

an open position of the transmitter key 1 disconnects a circuit whiclrmay be traced throughthe line. relay 3, contacts 11 of a control relay 10, a conductor 14, the windthe relay 10. to open the circuit of the extension line to the substation at that point.

-During moments the key 1 at substation C is closed, current in the winding :21 of the relay :20. over the circuits just traced, overpowers the current in the winding '22, thereby returning the arn'iature to disconnect the battery (3 and to connect the battery 5 to the line L. The resulting action at the distant end of the line is to oppositely bias the line relay and the control relay at that,

point and thereby close the extension line to the associated substation.

In tracing the, ope 'ations whereby messages from the distant substation are received at the substation C, let it be assumed that. in response to a change of polarity in the line L, the line relay 30 will be moved to its opposite bias. thereby connecting a batterv 8 through the control relay 1(). The

armature of the latter relay will be thereby moved to separate its contacts 11 and to close its contacts 12. The time relation ot these contacts is such that the contacts 12 will close before the contacts 11 separate and vice 'versa, foran opposite movement of the armature. Closure of the contacts 12 GSttIblISlNS a clrcult which may be traced from the battery 5 over the armature of the 40 relay 20, a resistance unit. 28. the winding 23 of'relay 20, a conductor '16, the contacts 12 of the relay 10, and a resistance unit 13, to earth. Due to the operating time relation of the contacts of the relay 10. as already described, a current through the winding 23. is established be ore cessation of current through the windii'ng 21 ot' the relay 20, and the polarity re ation of this circuit change is such that the armature of the relay 20 will be retained fin its normal position connecting with the battery 5. The 'circuitchanges set up by the relay 10, sub stitute the winding 23 for the winding :21 in establishing a circuit to overpower the etfect of current through the winding .22 and also the effect of the small accelerating ,current present in thewinding 24 of the relay 20. An impulse of current from the line L of opposite )olarity, will move the armature of the relay 30 to establish the battery 7 through the relay 10, thereby returning the armature of the latter relay to its normal position to close the contacts 11 and to separate the contacts 12. In this position the circuit of the line t to the substation is completed through the Winding 21 of the relay 20 over the circuits already traced while the direct current circuit through the Winding 23 of the latter relay is interrupted, all in a manner to not affect the normal position of its armature.

It will, therefore, be clear that for the receipt of messages from the line L the relays 3t) and 10 at the repeater station and the relay 3 and as ociated sounder at the substation are active while the pole changer relay 20 at the repeater station continues inert.

The self-aiding ctl'ect at the pole changer relay :20. is substantially the same for the correspomling relay in each figure of the drawing, the resistance of the units 28 and 20 being such that the current strength over the leak circuit through the rela winding 24, will be small compared with t e portion of the currents which branch through the line relay 30 .in the transmitting of messages outgoing over the duplexed line L.

It may also be mentioned that the characteristics of the windings 23 and 2-1 and the resistance unit :26 as well as condenser 27 are such that the discharge of this condenser will best meet the phase relation of the current changes set up by the transmitter key at the associated substation. It may be further pointed out that the equipment shown at A and C in Fig. 1 may be located at one end of a line circuit and op erated with equipment similar to that shown at A and C in either of the Figs. 2 and 3, and further that the. equipment shown in Fig. 22 may be employed at one end of a line to work in connection with equipment similar to that shown in Fig. 3 at the opposite end of a main line. 4

\Vhat is claimed is:

1. In atelegraph system. a first line section. a second line section. sources of current employed with equipment comprising a line relay. a control relay operated by said line relay to repeat messages in one direction between said line circuits, and a. sclfatiding relay rendered operative jointly by said line and said control relay for repeating telegraphic messages between said lines in the other direction.

2. Ina telegraph repeater system. a first line section and a second line section. sources of current employed with equipmentcomprising a line relay and a control relay for repeating telegraphic signals from said first to said second line section, a self-aiding relay for repeating telegraphic signals from said second to said first line section, and means operated by said control relay For rendering said self-aiding relay either operatlve or. non-operative.

3. In a telegraph repeater system,-a first and a second line section. sources of current; employed with equipment comprisingrelayv liz' and means confirollerl by said relay means self-controler seconrl r said-first lino section, nncl means i0 repeating; ielcgrapmc signuls' snirl lir i to said second line min i i i l ralil' of line circuits, sources of sin-rent employed with quip nt comprising r means for repeating signals beiu'ecn line sections in ons .riirccizpn, other line circuits in an opposite rlir ction controlled CiICilliZS anri contro CHCUliS for said mentioned to relay means in snbsiituie circuit for an sxterna'ily coin: of ssicl second in effect locking of the h ts-er relay In s telegraph repcstsr line section, a line relay. vi sources of can inena comprising senor control said second iin rcnci ring said line relay "1m. relay effective to rc psst Sign first to said second line sch-aiding relay means trolled circuits tor means, means renrlsrin relay elicciive to repeat opcraic l by said control rcla) to substitute a sf-lf-c n1trollo l circuit for an cxlcriorly cont-rolled circuit of said self-aiding relay nicans to (sifibllrill locking of the latter relay.

ii. in a tclegrapli repcai'cr 's'tcm, a plurality of line sections, sources of current employed Wli'll equi nnent comprising means for repeating telegraphic signals in one (lircoiion between said line sections, a selfaiding electroresponsive means for repeaticlegrapiiic signals between said line sec ions in an opposite direction, self-aiding circniz and exteriorly controlled circuits for said sell-aiding eleciroresponsive means, and means controlled by said first mentioned means for substituting a sclf-ai lingv for an oxteri-orly controlled circuit for locking said r cling eleciroresponsive means;

Zr In a telegraph repeater, a first linosec-- sion, in second line section, sources of current canning eel with equipment oomprisin g electroresnonsi'va means for repeating telegraphic sis from said first to said second line seii-aicling relay means for repeat lilo signals "from said second to iine sections, a local circuit means, insane, controlled by said e1ectr0responmeans for substituting said local circuit for said second line section in retainssicisel'f-airling relay means in its norposition.

Witness whereof, I hereunto subscribe. this 205L121 day of N0ven1bcr,A. D.

JOHN H. mm. 

